FlyKly Smart Wheel “looks like any other rear wheel, except that it has a monster-sized hub stuffed full of electronics,” Gizmodo says. It’s like the Prius of bike wheels — it stores energy as you pedal and while you’re going downhill. And then it uses that energy to speed you along, if you want, at up to 20 mph for 30 miles. It also can track your routes, speeds, and times, and suggest better routes.